Environmental impacts of seaweed cultivation: kelp farming and preservation

This chapter provides an overview of the environmental impacts of the supply chain for preserved seaweed. The supply chain includes the hatchery, marine infrastructure, deployment of juveniles and monitoring during cultivation (grow-out of seaweed), harvest, transport back to shore and preservation of the biomass. The chapter starts with a short overview of the life cycle assessment (LCA) methodology, and how it can be used to quantify the environmental impacts of seaweed supply chains. After a discussion of the overall environmental impacts of the preserved seaweed supply chain, the chapter focuses on specific life cycle stages: spore preparation and seeding of juvenile seaweed onto string in the hatchery, seaweed cultivation, harvesting preservation and storage of harvested seaweed. The chapter ends with a summary and discussion of future trends in the subject.

Nutritional and anti-methanogenic potentials of macroalgae for ruminants

The livestock production sector is facing challenges to find alternative feed resources and nutritional strategies to mitigate enteric methane (CH4) emissions from ruminants. Recently, marine macroalgae have emerged as potential anti-methanogenic feed ingredients due to their ability to suppress enteric CH4 production in ruminants. The anti-methanogenic properties of macroalgae have been ascribed to the contents of secondary metabolites, such as halogenated compounds e.g., bromoform in red species, and polyphenols or isoprenoids in brown species. These compounds may suppress methanogenesis by inhibiting the growth and activity of methanogens or by altering rumen fermentation pathways and the patterns of volatile fatty acids production. On the other hand, the anti-methanogenic macroalgae, particularly when added to diets in large amounts, are known to reduce animal performance, due to the presence of special and poorly degradable carbohydrates. Thus, finding a proper balance between the abilities to reduce CH4 emissions and sustain animal performance is important.